body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: #0f172a;
    color: #f8fafc;
    margin: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}
.container {
    text-align: center;
    width: 100%;
    max-width: 500px;
    padding: 20px;
}
h1 { font-size: 2.5rem; margin-bottom: 5px; color: #38bdf8; }
.subtitle { color: #94a3b8; margin-bottom: 30px; }
.menu-card, .panel {
    background: #1e293b;
    padding: 30px;
    border-radius: 16px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.3);
}
.btn {
    display: block;
    width: 100%;
    padding: 15px;
    margin: 15px 0;
    font-size: 1.1rem;
    font-weight: bold;
    text-decoration: none;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    box-sizing: border-box;
    transition: transform 0.2s;
    text-align: center;
}
.send-btn { background-color: #3b82f6; color: white; }
.receive-btn { background-color: #10b981; color: white; }
.btn:active { transform: scale(0.98); }
video, canvas {
    width: 100%;
    max-height: 350px;
    border-radius: 8px;
    background: black;
    object-fit: contain;
}
progress { width: 100%; height: 20px; margin-top: 15px; border-radius: 4px; }